Interlocking device for enclosed electric switch



Nov. 12, 1957 J. B. WALLACE El AL INTERLOCKING DEVICE FOR ENCLOSED ELECTRIC SWITCH Filed March 9, 1956 2 Sheets-Sheet 1 James 8. Wallace 8 Samuel S.Fouse ATTORNEY 1957 J. B. WALLACE ETAL 2,313,152

INTERLOCKING DEVICE FOR ENCLOSED ELECTRIC SWITCH Filed March 9, 1956 2 Sheets-Sheet 2 I J Ill/II III I Fig.2.

Fig.3.

United States Patent INTERLOCKING DEVICE FOR ENCLOSED ELECTRIC SWITCH James E. Wallace, Beaver, and Samuel S. Fouse, Aliquippa, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application March 9, 1956, Serial No. 570,596

7 Claims. (Cl. 200-50) Our invention relates, generally, to enclosed electric switches or circuit breakers and, more particularly, to interlocking devices for controlling the operation of switches or circuit breakers which are enclosed in cabinets having openable covers.

Heretofore, interlocking devices have been provided to prevent the door of the enclosing cabinet from being opened while the circuit interrupter is in the closed position. Interlocking devices have also been provided for preventing the closing of the circuit interrupter while the cover is open. However, the prior interlocking devices have been somewhat complicated in structure and have not been suitable for use with operating mechanisms of certain types.

An object of our invention, generally stated, is to provide an interlocking device for controlling the operation of an enclosed circuit interrupter which shall be simple and efficient in operation and which may be economically manufactured and installed.

A more specific object of our invention is to provide an interlocking device for an enclosed circuit interrupter which shall prevent the interrupter from being accidentally closed while the cover of the enclosure is open.

Another object of our invention is to provide an interlocking device which directly engages the operating handle of an enclosed circuit interrupter to prevent closing the interrupter while the cover of the enclosure is open.

A further object of our invention is to provide an interlocking device which normally prevents an enclosed circuit interrupter from being accidentally closed while the cover of the enclosure is open, but which may be manually released to permit closing the interrupter.

Other objects of the invention will be explained fully hereinafter or will be apparent to those skilled in the art.

In accordance with one embodiment of the invention, a spring-mounted interlocking member is disposed to engage the operating handle of an enclosed circuit interrupter to prevent closing the interrupter when the cover of the enclosure is open. When the cover is closed a part of the operating member carried by the cover moves the interlocking member out of the path of the interrupter handle as the operating member is moved to actuate the interrupter handle, thereby permitting the interrupter to be closed.

For a better understanding of the nature and objects of the invention, reference may be had to the following detailed description, taken in coniunction with the accompanying drawings, in which:

Figure 1 is a view, in plan, of a portion of an enclosed electric switch embodying the principal features of the invention;

Fig. 2 is a view, partly in side elevation and partly in section, of the structure shown in Fig. 1; and

Fig. 3 is a view, partly in section and partly in end elevation, of the switch structure.

Referring to the drawings, the structure shown therein comprises a portion of a sheet metal cabinet having an openable cover 11 which may be hinged at one end and fastened in the closed position by screws 12 (only one of which is shown) which may be threaded into angle brackets 13 secured to an end wall of the cabinet. If desired, the cover may be fastened by means of a spring-loaded latch in place of the screws 12. As shown, a circuit interrupter 14 is mounted on the back wall or bottom of the cabinet 10. The interrupter 14 may be a manually operable switch, or an automatic circuit breaker of the general type described in Patent 2,047,739, issued July 14, 1936, to H. J. Lingal, and assigned to the Westinghouse Electric Corporation.

The circuit interrupter unit 14 is provided with an op erating handle 15 which is moved about a pivot in one direction to close the contact members of the interrupter and in the other direction to open the contact members. If the circuit interrupter unit is an automatic circuit breaker the handle 15 will be automatically moved to a tripped position when the contact members of the circuit breaker are opened automatically by overload conditions.

An operating member or plate 16 is secured to one end of a stub shaft 17 which is rotatably mounted in the cover 11 and extends through the cover. An actuating lever 13 is secured to the outer end of the stub shaft 17. The lever 18 is of a type which is suitable for operation by means of a hook stick which may be inserted into openings 19 provided in oppositely disposed ears 21 on the lever 18. It will be understood that an actuating lever or handle of a type suitable for direct engagement by the hand of an operator may be utilized if desired.

As shown most clearly in Fig. l, the operating member 16 is provided with an opening 22 for receiving the handle 15 of the interrupter 14 when the cover 11 is closed. In this manner the circuit interrupter may be operated from the exterior of the cabinet by actuating the lever 18 about its pivot point which causes the operating plate or member 16 to actuate the interrupter handle 1.5, thereby operating the circuit interrupter. in order to reduce the friction between the operating member 16 and the handle 15 and also to reduce the torque exerted on the handle 15, the edges of the late 16 which engage the handle 15 are rounded at 23 as shown in Fig. 1.

An interlocking device (not shown) of a type described in Patent 2,215,299, issued September 17, 1940, to G. R. Runke and H. S. Gano and assigned to the Westinghouse Electric Corporation may be provided to prevent opening the cover 11 when the handle 15 of the circuit interrupter is in the closed position. Thus, the cover 11 normally cannot be opened while the contact embers of the circuit interrupter are closed and access to energized parts of the structure is prevented.

In addition to the foregoing interlocking device, it is also desirable to provide an interlock which will prevent the interrupter from being accidentally closed while the cover 11 is open. Interlocking devices for performing this function have been provided previously. However, the prior devices have been somewhat complicated in structure and in their manner of operation. In order to simplify the structure and operation of such interlocking devices, we have devised the present interlocking device.

As shown, one leg of an angle-shaped interlocking member 24 is attached to one leg of an angle-shaped spring member 25, the other leg of which is attached to the interrupter unit 14 by bolts or rivets 26. The angle member 24 may be composed of a fibrous impregnated material and it is attached to the spring member 25 by means of bolts or rivets 27. The spring member 25 may be composed of spring steel or other material having the desired characteristics. A sheet of insulating material 28 may be disposed between the member 25 and the handle 15 to prevent a phase-to-phase short circuit on overload, the switch 14 being a three-phase switch.

As shown most clearly-in Fig. 1, the one leg of the interlocking member 24 has a projection 31 which will be disposed in the path of movement of the handle 15 when the cover 11 is open, thereby blocking movement of the handle l to the on position to close the contact membersof the interrupter. When the cover 11 is closed and the operating member 16 is-moved to actuate the handle 15 to the-closed or on position, a pin or part 32, which is secured in the member 16, bears against the edge 33of the angle member 24 to move the projection 31 out of the path of movement of the handle 15 as shown by the broken lines in Figs. 1 and 3.

Thus, the circuit interrupter may be closed by operating the lever 18 in the normal manner when the cover 11 is secured-in its closed position by means of the screws 12. However, if the cover 11 is not fully closed, the pin 32 will not engage-the interlocking member 24 to move it out of the position to which it is biased by the spring member 25 to block movement of the interrupter handle 1-5 to-its on position to close the contact members of the interrupter.

In this manner accidental closing of the circuit interrupter while the cover 11 is open is prevented since movement oftheinterrupter handle 15 on the on position is prevented by the projection 31 on the interlocking member' 24 being in the path of movement of the handle. If it is desired to deliberately close the circuit interrupter while the cover 11 is open, the interlocking member 24 maybe moved out of the path of the handle 15 by an operator.

It will be noted that a portion of the interlocking member 24 is disposed directly in the path of movement of the handle 15 and engages the handle directly to prevent closing the interrupter. Furthermore, the pin 32, which en gages the interlocking device directly to release the interlock, is carried by the operating member 16 and moves with the operating member. Thus, the interlocking device engages the operating handle 15 directly to prevent closing the interrupter, and the operating member 16 engages the interlocking device directly to release the interlocking device. In this manner the structure and operation of the interlocking device are simplified as compared with prior interlocking devices for performing the same function.

From the foregoing description it is apparent that we have provided a simplified and improved interlocking device for preventing accidental closing of an enclosed circuit interrupter when the cover of the enclosure is open. The present interlockingdevice may be coordinated with interlocking devices which normally function to prevent opening the cover of'the enclosure while the circuit interrupter is closed.

Sincenumerous changes may be made in the above described construction and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all the matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Weclaim as our invention:

1. In an electric switch, in combination, a cabinet having an openable cover, a circuit interrupter unit disposed in the cabinet and having an operating handle, an operating member carried by the cover and engaging the operating handle when the cover is closed, a. springmounted member disposed to engage the operating handle to prevent closing the interrupter when the cover is open, and'said spring-mounted member being actuated by movement of said operating member to permit closing the interrupter when the cover is closed.

2. In an electric switch, in combination, a cabinet having. an, openable cover, a circuit interrupter unit disposed inthe cabinet and having an operating handle, anioperating member carried by the cover and engaging the operating handlewhenthe. cover is. closed, a spring biased. member 4 mounted on the interrupter unit and disposed to engage the operating handle to prevent closing the interrupter when the cover is open, and said operating member moving said spring biased member to permit closing the interrupter when the cover is closed.

3. In an electric switch, in combination, a cabinet having an openable cover, a circuit interrupter unit disposed in the cabinet'and having'an. operating handle, an operating member carried by the cover and engaging the operating handle when the cover is closed, an interlocking member mounted on the interrupter unit, spring means for moving the interlocking member into the path of the operating handle to prevent closing the interrupter when the cover is open, and said operating member moving the interlocking member out of the path of the operating handle when the operating member is actuated to close the interrupter when the cover is closed.

'4. In an electric switch, in combination, a cabinet having an openable. cover, a circuit interrupter unit disposedin the cabinet and having an operating handle, an operating member carried by the cover and engaging the operating handle when the cover is closed, an interlocking member mounted on the interrupter unit, spring means for moving the interlocking member into the path of the operating handle to prevent closing the interrupter when the cover is open, and said operating member engaging the interlocking member to move it out of the path of the operating handle as the operating member is being actuated to close the interrupter when the cover is closed;

5. In an electric switch, in combination, a cabinet having an. openable. cover, a circuit interrupter unit disposed in the cabinet. and having an operating handle, an operating member carried by the cover and engaging the operating handle when the cover is. closed, an interlocking member mounted on the interrupter unit, spring means for moving the interlocking member into the path ofthe operating handle to prevent closing the interrupter when the cover is open, and means on the operating member for moving the interlocking member out of the path of the operating handle each time the operating member is actuated to close the interrupter when the cover is closed.

6. In. an electric switch, in combination, a cabinet having an openable cover, a circuit interrupter unit disposed in the cabinet and having an operating handle, an operating member carried by the cover and engaging the operating handle: when the cover is closed, a spring biased member mounted on the interrupter unit and disposed in the path of. the operating handle to prevent closing the interrupter when the cover'is open, and means on the operating member engaging said spring biased member to move it out of the path of the operating handle when the operating member is actuated to close the interrupter when the cover is closed;

7. In an electric, switch, in combination, a cabinet having an openable cover, a circuit interrupter unit disposed in the cabinet and having an operating handle, an operating member carried by the cover and engaging the operating handle when the cover is closed, a springmounted member disposed in the path of the operating handle to prevent closing the interrupter when the cover is open, and projecting means on the operating member engaging said spring-mounted member to move it out of the path of, the operating handle as the operating member is being actuated to close the interrupter when the cover is closed.

References Cited in the file of this patent 

